High Strength Materials

Question 1

Name the two types of high-strength materials

Answer 1

• Intermetallics

- Superalloys

Question 2

How are superalloys defined?

Answer 2

Alloys which have useful levels of mechanical properties (including good “creep resistance”) above 600-700 degrees celcius

Question 3

What are the main alloying elements for super alloys?

Answer 3

• Nickel
• Cobalt
• Iron

Question 4

Name the 4 additional alloying elements in superalloys

Answer 4

Chromium, Aluminium, Titanium, Copper

Question 5

Name the three types of superalloys

Answer 5

• Nickel based (Ni > 50%)
• Cobalt based (Co > 50%)
• Nickel-Iron based (Ni+Fe > 50%)

Question 6

Main advantages of superalloys

Answer 6

• High Tensile strength at high temperatures
• High heat, corrosion and oxidation resistance
• High creep resistance
• High fatigue life

Question 7

3 Main Applications of superalloys

Answer 7

• Nuclear Power Plant
• Aerospace engine parts
• Gas Turbines

Question 8

What are the 5 types of stainless steels

Answer 8

• Austenitic
• Ferritic
• Martensitic
• Duplex
• Precipitation-Hardening

Question 9

Name the two elements usually present in Ferritic (Martensitic) stainless steel

Answer 9

Iron and Chromium

Question 10

Name the three elements usually present in Austenitic Stainless Steels

Answer 10

Iron, Chromium and Nickel

Question 11

What is the crystal structure and magnetic property of Ferritic stainless steels

Answer 11

BCC and Ferromagnetic

Question 12

What is the crystal structure and magnetic property of Austenitic stainless steels

Answer 12

FCC and Paramagnetic

Question 13

Is corrosion resistance higher or lower in ferritic steel compared to austenitic steel

Answer 13

Lower

Question 14

Is strength (hardness) higher or lower in ferritic steel compared to austenitic steel

Answer 14

Higher

Question 15

Is cost higher or lower in ferritic steel compared to austenitic steel

Answer 15

Lower